The present invention relates to a device for stopping the movement during time-setting of a watch fitted with a tourbillon, the tourbillon comprising a rotating carriage inside which a balance oscillates about a rotational axis of the carriage, the device comprising manually controlled means for blocking the balance in its peripheral zone.
Such a device, sometimes called a “stop-second”, has already been proposed for stopping the oscillation of the balance in the tourbillon carriage when the time is being set, in any position of the carriage, from the control stem of the watch in order to start the movement at a precise moment, for example exactly at the time indicated by the hands of the watch.
There is a description of this device given in DE Patent Application No. 101 60 287 A1 repeated in International Patent Application WO 03/048871. In a manner that is well known in the state of the art, the tourbillon comprises a mobile carriage, which carries all of the escapement members and, at its centre, the regulating member comprising the balance. The escapement pinion rotates about the second wheel which is fixed. The carriage makes one revolution per minute and eliminatesrate variations by rotating when it is in vertical positions. In order to stop the movement, the aforecited document proposes a mobile spring with two elastic arms, each ending in a pad able to abut elastically against the periphery of the balance to stop it. This mobile spring is controlled by the time setting crown, which is also manually controlled.
This device has, however, several drawbacks. First of all, the mobile spring is complicated to make, since, because of its great length, it also requires an adjustment that is difficult to carry out. Another drawback lies in the fact that a spring of such length can easily be deformed via the effect of a shock applied to the watch and thus inadvertently block the balance. Finally, it will be mentioned that in top of the range horology, the use of a wire spring or strip spring is generally prohibited, as it is unattractive and offers solutions that are ill-suited to a highly technical object.